Field of the Invention
The present invention relates to ferroelectric ceramics and a manufacturing method thereof.
Description of a Related Art
A conventional manufacturing method of a Pb(Zr,Ti)O3 (hereinafter, referred to as “PZT”) perovskite-type ferroelectric ceramic will be explained.
A SiO2 film having a thickness of 300 nm is, formed on a 4-inch Si wafer, and a TiOx film having a thickness of 5 nm is formed on the SiO2 film. Next, a Pt film having a thickness of 150 nm, oriented in, for example, (111) is formed on the TiOx film, and a PZT sol-gel solution is applied onto the Pt film by using a spin coater. Spin conditions at this time are such that the wafer is rotated at a rotational speed of 1500 rpm for 30 seconds and is rotated at a rotational speed of 4000 rpm for 10 seconds.
Next, the applied PZT sol-gel solution is heated and held on a hot plate at 250° C. for 30 seconds to thereby be dried, and moisture is removed, and after that, is additionally heated and held for 60 seconds on a hot plate maintained at a high temperature of 500° C. to thereby perform temporary calcination. A PZT amorphous film having a thickness of 150 nm is produced by repeating this for several times.
Subsequently, an annealing treatment is performed on the PZT amorphous film at 700° C. by using a pressurizing-type lamp annealing device (RTA: rapidly thermal anneal) to thereby carry out PZT crystallization. The PZT film thus crystallized is formed of a perovskite structure (refer to, for example, Patent Literature 1).
[Patent Literature 1] WO 2006/087777
[Patent Literature 2] Japanese Patent Laid-Open No. 11-312801